The two main rebel groups in the region, which borders Damascus, have firmly and repeatedly denied negotiating with the Syrian regime.

But on Sunday, as the government's Russian-backed assault entered its fourth week, influential figures in one rebel-held town were considering a possible evacuation offer.

A committee from Hammuriyeh met with regime representatives on Saturday, a member of the committee told AFP, speaking on condition of anonymity.

"The committee discussed a proposed reconciliation that would guarantee exit for those that want to leave, both civilians and rebels, from Hammuriyeh to other areas in Syria under rebel control," the delegate said.

Civilians and fighters could be bussed to rebel-controlled parts of Daraa province in Syria's south, or to Idlib in the northwest, held by rebels and a former Al-Qaeda affiliate.

Government forces would then take control of Hammuriyeh, and residents who wanted to stay on in the town would be allowed to do so.

"The committee is meeting on Sunday to take a decision and inform the regime. If they do not agree, there would be a resumption of the military operation on Ghouta, including Hammuriyeh," the negotiator added.

Following weeks of bombing, it was relatively quiet in the town throughout the night and into Sunday.

In recent years, the regime has recaptured several areas around Damascus from rebels by pursuing fierce military offensives culminating in evacuation deals.

The Syrian Observatory for Human Rights, a Britain-based war monitor, said negotiations for evacuations from multiple towns were ongoing Sunday.

"A decision could be taken any moment for Hammuriyeh, Jisreen, and Saqba," said Observatory chief Rami Abd al-Rahman.

All three towns are controlled by Islamist rebel group Faylaq al-Rahman, which has repeated denied engaging in talks with the regime.

"There are no direct or indirect negotiations with the Russian enemy or its allies," said the group's spokesman Wael Alwan late Saturday.

"No one has been authorised to negotiate on behalf of" rebels in Ghouta, he added.

The second main rebel group in Ghouta, Jaish al-Islam, has also denied rumours it is negotiating its own withdrawal.

But it has admitted engaging in talks with the United Nations and world powers on Hayat Tahrir al-Sham (HTS), a jihadist group once linked to Al-Qaeda.

Those negotiations resulted last week in Jaish al-Islam releasing 13 HTS members it was holding. The jihadists and their relatives were then evacuated to northwest Syria Friday.

HTS, which has a small presence in parts of Ghouta, has not commented publicly on the negotiations.

Russian news agency Interfax said Sunday that the Russian Centre for Reconciliation, based alongside Russia's air force at the Hmeimim military airport in western Syria, was facilitating negotiations with rebels in Ghouta.

It did not specify which rebel factions were engaging in the talks.

"The fighters are considering the possibility of evacuating several dozen residents in exchange for an opportunity to leave the area with their families," a representative of the centre, officer Vladimir Zolotukhin, told Interfax.